Heat Pump Noise & UK Planning Permission: MCS 020 Standards Explained
A clear guide to England & Wales Permitted Development Class G regulations, sound power decibels (dBA), and siting your outdoor unit to avoid neighbour disputes.
📌 Key Takeaways & Statutory Facts:
- Under Permitted Development Class G in England, air source heat pumps do NOT require planning permission if standard conditions are met.
- The outdoor unit must be at least 1 metre from the property boundary.
- The installation must comply with the MCS 020 sound calculation standard (< 42 dBA at the nearest neighbour's assessment position).
- Leading modern heat pumps (Mitsubishi Ultra Quiet, Vaillant aroTHERM Plus, NIBE S2125) operate between 26–30 dBA at 3 metres—quieter than a refrigerator hum.
- Listed buildings and conservation areas may require localized Listed Building Consent.
Fear of noise is the #2 reason homeowners hesitate to install an air source heat pump. Horror stories of loud droning fans usually trace back to poorly installed commercial air conditioners from 15 years ago. Modern purpose-built domestic heat pumps are astonishingly quiet.
Permitted Development Rights in England (Class G)
In England, domestic air source heat pumps are classified under Permitted Development Rights, meaning you do not need to submit a formal planning application provided you meet these criteria:
- The heat pump is used solely for heating purposes.
- There is no other air source heat pump on the property or curtilage.
- The outdoor unit compressor volume does not exceed 0.6 cubic metres.
- The unit is located at least 1 metre from the boundary of the curtilage.
- The installation complies with the MCS 020 Planning Standard for Noise.
The MCS 020 Noise Calculation
Before installing, your MCS engineer performs an acoustic calculation based on the manufacturer's Sound Power Level (LwA), the distance to the nearest neighbour's habitable room window, and any reflecting surfaces (walls, fences). The sound level reaching the neighbour's window must not exceed 42 dB(A).
With units like the Mitsubishi Ecodan (26 dBA @ 3m) and Vaillant aroTHERM Plus (28 dBA @ 3m), meeting MCS 020 is straightforward even in typical suburban semi-detached and terraced garden plots.
Check Your £7,500 BUS Grant Allocation & Local Installers
Under the statutory Boiler Upgrade Scheme (BUS), UK homeowners qualify for an upfront £7,500 non-repayable voucher with 0% VAT. Check vetted local MCS heating engineers covering your postcode.
Claim Your £7,500 BUS Grant & Match Local Installers
Connect with accredited local MCS heating engineers in your area. Free room heat-loss assessment and £7,500 grant deducted upfront on your invoice with 0% VAT.
Check Your Grant Eligibility
Use our live calculator or 3-tap quiz to discover your property's net installation price.